The cumene process in which phenol is produced from cumene as a starting material is known. The cumene process gives by-product acetone in an equimolar amount to the phenol produced. The by-product acetone has a wide range of applications as solvent or organic synthesis material. However, depending on market trends which differ at different times, the acetone by-produced is in excess or the market conditions thereof are adverse, thereby lowering economic efficiency of phenol. The cumene is usually produced by alkylating benzene with propylene. The propylene is manufactured by thermal cracking of naphtha. Depending on the demand balance between propylene and ethylene which is another product by the naphtha cracking, propylene shortage is often brought about which is a bottleneck in the production for cumene.
To avoid the bottleneck, Patent Literature 1 discloses a process in which acetone by-produced in the phenol production is hydrogenated to isopropanol, the isopropanol is dehydrated to propylene, and the propylene is recycled as a material in the cumene production or the like. However, the hydrogenation and the dehydration add two steps.
To reduce steps, Patent Literatures 2 to 4 disclose methods in which isopropanol from the hydrogenation of acetone is directly used as an alkylating agent without dehydration and is reacted with benzene to give cumene. Patent Literature 4 discloses that the process involves a trickle-bed reactor, but is silent on the flow rate of gas.